Increasing ‘R’ factors, or reproduction rates, of the coronavirus in Maharashtra and Kerala have triggered concerns of a renewed wave of COVID-19 cases in these states – one that could fuel a national spike in cases and trigger a third wave of infections and deaths.
An increasing ‘R’ value means news that several states – including Maharashtra – are reporting fewer new cases every day should be viewed with caution, as must a falling national active caseload that, Monday morning, was 4.5 lakh – the lowest since late-March.
Maharashtra – which reported 8,535 new infections on Sunday to add its active load of 1.19 lakh cases – has seen its ‘R’ factor climb from 0.79 in mid-May to 0.84 by May 30 and 0.89 by end-June. The most recent data indicates its ‘R’ factor is now close to 1.
Kerala – which reported 12,220 new cases to take its active load to 1.15 lakh – saw its ‘R’ factor cross the dreaded 1.0-mark earlier this month before dipping back below, and recent data suggests it remains dangerously close to that level.
“The difference seems small… but it indicates exponential rate of increase. Even a .1 change can make a big difference going forward, in terms of how many active cases there will be,” Dr Sitabhra Sinha, lead researcher at Chennai’s Institute of Mathematical Sciences, said.
Of equal concern is the ‘R’ factor in several north-eastern states; in Manipur it is greater than 1. Last week data from the central government showed rapid transmission in the area, with 47 of the 73 districts in India that reported a positivity rate of over 10 per cent in the northeast.
“It is worrying that a few states are slowing down the rate of resolving active cases or, in some instances, have ‘R’ factor close to 1… a little nudge can push it the wrong way,” he cautioned.
The ‘R’ factor – a statistic used worldwide to track, and potentially, control the spread of the virus – is a measure of how many people are being infected by one infected person.
An ‘R’ value of 1 means one person will, on average, infect one other person.
In a pandemic situation the ‘R’ target is less than 1.0, which ensures the virus will eventually stop spreading because it cannot infect enough people to sustain the outbreak.
“What this tells you is that if 100 people are infected, they can only pass it on to 98 at most. A falling ‘R’ value means fewer and fewer people are infected in the future,” Dr Sinha explained.
“If this number is high, there is (also) a high chance of a ‘super-spreader’ event,” he added.
The national ‘R’ factor is 0.95 (a seven-day moving average), and it too has seen a steady (and very unwelcome) increase – up from .87 last week and 0.74 four weeks ago.
At the peak of the second wave – when more than four lakh new cases were reported in 24 hours and thousands died daily – the national ‘R’ value was estimated at 1.37.
This morning India reported 37,154 new COVID-19 cases (and 724 deaths) in 24 hours.
The declining case numbers have led several states to relax restrictions imposed during the height of the second wave – relaxations that, some experts fear, could trigger a fresh spurt of cases.
The government – reacting to shocking images from crowded hill stations and city markets – has warned people against believing the pandemic and virus has been beaten.